1. Field of the Invention
The present invention relates to slopeboard mountings for use with bulldozers and other earth moving vehicles.
2. Description of the Prior Art
Bulldozers have for years been used in landscape grading in connection with residential and commercial construction. In recent years an auxiliary blade, known as a slopeboard or mold board has gained in increasing usuage as an auxiliary earth contouring device. The slopeboard, as conventionally attached to an earthmoving vehicle, is mounted for extension to one side of a main bulldozer blade. The slopeboard is hydraulically or pneumatically actuated and may be raised to extend from the base of a lower corner of the bulldozer blade upward at an angle, or lowered to slant downward from the bulldozer blade corner, extending below the level thereof. This later application is only possible where the terrain slopes downward from the level of the bulldozer.
Although slopeboards have been widely utilized, their attachment to a bulldozer blade, or to the vehicle itself, has heretofore been accompanied by numerous problems. Usually the slopeboard blade is attached directly to an unreinforced portion of the main bulldozer blade. The resulting structure is somewhat unwieldy and definitely lacks structural integrity. That is, because the slopeboard is in effect hung from and supported by the bulldozer blade, considerable flexure of the slopeboard blade results when the earthmoving vehicle is in motion and the slopeboard blade is used to contour the landscape. As a result, the soil appearance of ground terraced by the slopeboard is irregular due to the halting, jerking movement of the slopeboard thereacross. In addition, the slopeboard mounting frequently becomes bent and deformed, and quite often fractures, thereby requiring repairs and disabling the vehicle while such repairs are performed. As a consequence, in conventional usage a slopeboard is utilized only for very light terracing.
A further problem found with conventional slopeboard mounting arrangements is the inflexibility of blade disposition. Typically, a blade can be raised only to a relatively small acute angle, such as 45.degree. or 50.degree. with respect to level terrain. Even when the slopeboard blade is not in use the earth moving vehicle, cannot pass close to trees and structures on the slopeboard side. This seriously limits the movement of the vehicle and adds extensively to the time required to landscape an area, since the bulldozer operator must constantly reposition the earth moving vehicle so that the slopeboard does not interfere with landscaping efforts using the main bulldozer blade near objects or structures in the vicinity.
A further problem with conventional slopeboard mounting systems is the failure to properly provide a smooth, even flow of dirt from the main bulldozer blade onto the slopeboard blade. In many conventional systems, the mounting arrangement includes attaching structure positioned on the front side of the main bulldozer blade. This seriously disrupts the flow of dirt off of the main blade and into the path of the slopeboard blade. As a result, longitudinally extending ridges are formed behind the bulldozer as it moves forward. In other systems, in which the slopeboard is mounted behind the main bulldozer blade, the separation is mounted behind the main bulldozer blade, the separation therebetween is so large that the slopeboard blade and the bulldozer blade plow at different levels in an area of overlap. As a consequence, furrows and ridges are frequently formed in the trial of the path movement of the earth moving vehicle.